有这样一道题:“计算(2x^3-3x^2y-2xy^2)-(x^3-2xy^2+y^3)-(x^3+x^2y+y^3的值,其中x=1/2,y=-1".同学1把x=1/2错抄成x=-1/2,同学2把“x=1/2”写成“x=2:“ 但他们的计算结果却是正确的,你说这是怎么回事?
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/16 22:52:14
![有这样一道题:“计算(2x^3-3x^2y-2xy^2)-(x^3-2xy^2+y^3)-(x^3+x^2y+y^3的值,其中x=1/2,y=-1](/uploads/image/z/1260585-9-5.jpg?t=%E6%9C%89%E8%BF%99%E6%A0%B7%E4%B8%80%E9%81%93%E9%A2%98%EF%BC%9A%E2%80%9C%E8%AE%A1%E7%AE%97%282x%5E3-3x%5E2y-2xy%5E2%29-%28x%5E3-2xy%5E2%2By%5E3%29-%28x%5E3%2Bx%5E2y%2By%5E3%E7%9A%84%E5%80%BC%2C%E5%85%B6%E4%B8%ADx%3D1%2F2%2Cy%3D-1%22.%E5%90%8C%E5%AD%A61%E6%8A%8Ax%3D1%2F2%E9%94%99%E6%8A%84%E6%88%90x%3D-1%2F2%2C%E5%90%8C%E5%AD%A62%E6%8A%8A%E2%80%9Cx%3D1%2F2%E2%80%9D%E5%86%99%E6%88%90%E2%80%9Cx%3D2%EF%BC%9A%E2%80%9C+%E4%BD%86%E4%BB%96%E4%BB%AC%E7%9A%84%E8%AE%A1%E7%AE%97%E7%BB%93%E6%9E%9C%E5%8D%B4%E6%98%AF%E6%AD%A3%E7%A1%AE%E7%9A%84%2C%E4%BD%A0%E8%AF%B4%E8%BF%99%E6%98%AF%E6%80%8E%E4%B9%88%E5%9B%9E%E4%BA%8B%3F)
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